Team Sky's Tour de France line-up will be announced next week but the Guardian understands that eight of the nine riders have been decided by the team principal Dave Brailsford. Bradley Wiggins will lead the squad in their debut Tour, with two other British riders, Steve Cummings and Geraint Thomas, set to be included.

The other five definites are understood to be Juan Antonio Flecha of Spain, the Norwegians Edvald Boasson Hagen and Kurt Asle Arvesen, Thomas Löfkvist of Sweden and Simon Gerrans of Australia. Michael Barry of Canada, Sylvain Calzati of France and Greg Henderson of New Zealand are believed to be the riders still under consideration.

If there remains a degree of uncertainty around the identity of the riders who will go to the Tour, there is none about the team's raison d'être. It will be built around Wiggins as the British rider sets out to follow last year's fourth-place finish, though Boasson Hagen will be expected to challenge for stage wins, as will Henderson, the team's sprinter, if he is selected.

Otherwise the experienced Flecha and Arvesen, together with Cummings – who is making his Tour debut – will act as domestiques for Wiggins on the flat stages, with Löfkvist and Gerrans providing back-up for the Englishman in the mountains.

Wiggins has stepped up his preparation this week with a reconnaissance of some of the Tour's key stages. It began in the Alps on Monday, has continued in the Pyrenees (FRI), and will conclude on Saturday with a rehearsal of the potentially decisive penultimate time trial stage in Bordeaux.

It is the first time Wiggins has undertaken such a mission, and the scale of the week-long reconnaissance indicates the seriousness with which Team Sky are approaching July's Tour, with Wiggins accompanied by seven staff and two team-mates in Cummings and Barry.

Brailsford is not there, running the rule over his Tour team contenders at the Tour of Switzerland instead, but Rod Ellingworth, the race coach, and Sean Yates, the sports director, have joined Wiggins, along with a mechanic, soigneur, physiotherapist, performance analyst, and even the team chef.

Wiggins was caught out last year when he found himself in contention for the podium but oblivious to the challenges that lay ahead, having not ridden any of the route in advance. He admitted later that a rest day dash in a helicopter to look at the time trial stage in Annecy hardly compensated for having not checked the Tour's decisive climbs. This year, it is clear that he is taking no chances.